Control system for rewinder reel drives



Aug. 15, 1950 A. T. BACHELER ETAL 2,519,218

CONTROL SYSTEM FOR REWINDER REEL DRIVES Filed May 14, 1949 V I7 l8 I9 24 l 23 28 g 3o 26 WITNESSES: A b T BINVENITORsd e 0C e 8| on 547%? ThomosMGreer.

ATTO NEY Patented Aug. 15,1950

CONTROL SYSTEM F OR REWINDER REEL DRIVES Albert T. Bachelor, Wilkinsburg,

and Thomas M.

Greer, Pittsburgh, Pa., assignors to Westinghouse Electric Corporation,

East Pittsburgh,

Pa., a corporation of Pennsylvania Application May 14, 1949, Serial No. 93,298 8 Claims. (Cl. 318-7) This invention relates to electric control systems for rewinder drives. Such drives serve to wind textile, paper, metal, or other material from one reel core to another in one or the other winding direction, usually at a substantially constant speed of linear travel and within a given range of tension of the material. This requires one reel motor to increase its revolving speed while the material is unwound from the appertaining reel core, While the motor for the take-up reel decreases its speed as the diameter of the appertaining reel of material is building up. For some applications, such as in a dye jig, the reel drive must be reversible so that the material can be passed back and forth between the two reels for repetitive fabricating or processing operations,

It is an object of our invention to provide a rewinder drive control system which satisfies the above-mentioned requirements by means of a very simple circuit design whose torque-regulating performance does not rely on the use of reeloperated rheostats or other contact or slide-contact devices, such as dancer roll operated rheostats.

It is another object of our invention, subsidiary to the one mentioned, to provide a rewinder drive control system whose reel motors have armature circuits of utmost simplicity that do not require the insertion of power consuming devices for performing the desired speed or tension control.

In order to achieve these and the more specific objects apparent from the following description, we connect the armatures of the two correlated reel drive motors in series to a source of current so that both armatures are traversed by the same current in the respective directions needed to have each motor exert a torque in the wind-up direction. We further connected the respective field windings of the motor in a network, preferably of the bridge type, which is energized from two voltage sources so that their voltages are cumulative for the field of one motor and differential for the field of the other motor. One of the sources provides a normally constant volt age, while the other source is a regulator, preferably of the amplifying type such as an amplifying generator, and provides a variable regulating voltage under control by the sum of the respective voltages across the two motor armatures.

While these and other features of our invention are set forth in the appertaining claims, a more detailed example and explanation are given in the following description with reference to the drawing which shows diagrammatically a rewinder drive control system for a dye jig.

In the drawing, a trough for the dye is denoted by l. lwo rolls or reel cores 2 and 3 are provided for passing the textile or other web material 4 through the dye. The material passes from roll 3 over guiding devices such as the immersion rolls 5 and 6 through the liquid and onto the roll 2. When the reel of material on roll 3 has decreased to a minimum diameter, the traveling direction of the material is reversed, and the repetitive cycle is continued until the dyeing process is terminated. It is desired that the linear speed of the web material as it passes through the dye be approximately constant in order to obtain a uniform dyeing effect. The tension of the material should stay within limits that are safe for the material.

The reel core 2 is connected with l of a motor MI Whose field winding is denoted by 8. Similarly, the reel core 3 is in connection with the armature 9 of a second reel motor M2 with a field windin It. The connection between each motor armature and the reel core is schematically illustrated by a broken line. It normally consists of a speed-change gear or other mechanical transmission.

The two armatures 1 and B are series connected with current supply means represented by a generator G with an armature II and a separately excited field winding 12. Field winding l2 receives excitation from direct current buses I t and 15 of substantially constant voltage. A control rheostat [6 may be series connected with field winding I2. The buses i4 and 15 may be energized from an available direct current line or by means of an exciter which may be driven at constant speed together with the armature ll of the generator G or together with the armature of the regulating generator R mentioned below.

The field windings 8 and I ll of the two reel motors are connected in a bridge circuit which includes two resistors I! and i8 and has two pairs of diagonal points l9, it and El, 22. The diagonal points l9 and 20 are connected to the constant voltage buses i4 and i 5. It will be recognized that the two field windings 8 and I0 lie in different branches of the bridge loop circuit so that they are connected in parallel with each other relative to the constant voltage supply buses.

Connected between the other diagonal points 2! and 22 of the bridge circuit is the output circuit of a source of variable regulating voltage. This source consists of a regulator, preferably an amplifying generator. Various types of amthe armature I plifying generators are available for such regu- 3 latin purposes. The one exemplified by the drawing has its armature 23 connected with a self-exciting field winding 24 Whose excitation is tuned by means of a resistor 28 so as to approximately coincide with the ascendin unsaturated and substantially linear portion of the no-load saturation characteristic of the generator so that it supplies most of the excitation needed to maintain the output voltage of the generator at any value along the just mentioned linear por: tion of its characteristic. We prefer adjusting the self-exciting field of the regulating generator R to an undertuned condition so that the self excitation of this machine is somewhat below that required to sustain its output voltal'gl This prevents speed build up during thewinding. operation and reduces speed variations, thus improv ing the stability of the winding performance.

Regulating generators of the type applicable for the invention require additional control field in order to shift the output voltage "to higher oriower values along the characteris'ti'ci the drawing, the additional windings of gel eratQr R are denoted by 25, 2-6 and 21-. Winding "2-5 provides a normally constant pattern field or adjustable magnitude and is connected across the constant voltage buses Hand through a reversing switch 28- andin series with an adjusti'ng mea re: to. @he heldwinding '26 is com netted-across the motor armature 9 to be excited-in accordance with the voltage across the armature Field winding 21 is similarly con nectea'acrossme motor armature i; The field windings itahd Ziprov'ide cumulative pilot excitation for the regulating generator R in opposition to the fie-id of'patte'r-n field winding 255' :It was mentioned that motor field wfindir-igs 8-. are connectewl in parallel to each other across the con tant voltage buses I "and {-5. Relative to the aature circuit of the regulating generator R, he. the two field windings 8 and. 513- are '"o in series relation to each other. variable regulating volt-. -ator is addi. ve in one 'a-e to the constant com potent as these windings supplied from the comet it v e buses. Gonsequently, a gt .a ig voltage has the effect of optimum re: i-igs shouldhe ate mainly within. the unsaturated 7 r characteristics throughout thedesired ran e ofcontro'l. w

'The "two 'pi-lot field windings and Zi provide a cofitrol field ter the regulator 'R whose strength is proportional to the absolute sum bf the two you ges of-motors Mi andld-QL em as described above permits H vinding operation while maihta run I linear driving speed appro mately at a value d'e: terminedby the selected setting of the pa an field rheostat 3i! and also maintains the tension the Winding material with satisia'ctory rrow limits. However, for obtaining accurate results, especially as regards the tension control, thee i rent. supply means ior-energi'zingthe motor armatures should i'urnish a substantially constant eta-em. For that reason, we'prefe'r using "generator or substantially constant output current, such generators being known and available under the name shovel type'generator. I

With the armature currents of motors-Mi and M21 being constant, the armature voltages apsubtractive in the other n goiie motor field whileiveakening vmotors are so connected that each exerts torque the direction to wind up the material on its own reel. This introduces tension into the material. If we now assume that, at the just consid'ered momentfone of the motors is exerting more torqu'e than the other because of the difference in the strength of the respective motor fields, then the. stronger motor operates as a drive and overhauls the other motor which then operates as a generator. I; no limit were placed on the reca t which could be obtainedfrom the power supp g nerato'rG, then thedrive would lceep massa es-m However, since the fieids of the two motors are controlled-by the 'regulator Bin such "arranger as t'o'holdconstantthe sum of the-two motor armature voltages, the speed of t material is estaiilished ataii appr'oximateiy censtant vaiue from empty to Ifull -feel. As the growing re e'i's bu up, the will tend-to due to-tlie increase torque regu ifre- 'e t k 'un d t e weat n rrn'ature'v i ges of the two motors will; then tend to decrease. "its a result, the pilot field-pf the regulator R incl s a control action which changes the output voltagaof; the"regulator and henee varies the respective xcitationo'f fie-id 8 and It in the sense required to increase the sum of} the armature voltages. "Thus the windas motor fieldbe'cornes 5 ciiger and this motor exerts more torque. Th regi attestatio con; tilnues Tr'omemp y to "ull wind -up reel diameter. It'w-iil be recognized that the"control system performsthe sp'e'e and tension controlling rune-1 trons despite the'fact that no direct Incas ments of speed and tension are, required. a result, the desired oer atio "(iti' ivelj hy means of m? a t- 1 s st m tenements thigh require time s; iis i is eu n m inr terranee, it is assumed-in'forego-ing descript; n of the illustrated example "t h reel 'd ve 13s stswi ch tuses. wa ters d s:- en f he. i e

plated another cumulatively resistorv $8 In voltage I of the regulating source" strengt iens one motor field andwealsens't than those 'sp'eci closure and consequently may be incorporated in diagrams other than the one shown on the drawing, without departing from the essence of the invention and within the essential features defined by the claims annexed hereto.

' We claim as our invention:

1. A- control system for a rewinder drive, cornprising two winder motors each having an armature and a field winding, current supply means, said two armatures being connected in series with each other to said current supply means with such polarities of connection as to produce respective torques in the wind-up sense, constant voltage supply means, said two field windings being connected in parallelto each other to said voltage supply means, a regulator having an output circuit for providing variable regulating voltage and having two control circuits for jointly controlling said regulating voltage, said two field windings being also connected with said output circuit so that said regulating voltage strengthens the resultant excitation of one and weakens that of the other winding, and said control circuits being connected across said respective armatures for controlling said regulator to maintain the sum of the voltages across said armatures substantially constant.

2. A control system for a rewinder drive, comprising two winder motors each having an armature and a field winding, current supply means, said two armatures being connected in series with each other to said current supply means with such polarities of connection as to produce respective torques in the wind-up sense, a bridge circuit having four loop-connected branches and two pairs of diagonal points, voltage supply means of substantially constant voltage connected across one pair of said points, a regulator having an output circuit connected across said other pair of points to provide variable regulating voltage, said field windings being disposed in different branches of said bridge circuit so that said constant voltage and said regulating voltage are additive in one winding and subtractive in the other, said regulator having two cumulative control circuits for jointly controlling said regulating voltage, and said control circuits being connected across said respective armatures.

3. A control system for a rewinder drive, comprising two winder motors each having an armature and a field winding, current supply means, said two armatures being connected in series with each other to said current supply means with such polarities of connection as to produce respective torques in the wind-up sense, a bridge circuit having four loop-connected branches and two pairs of diagonal points between said branches, constant voltage supply means connected across one pair of said bridge points, said field windings being disposed in adjacent branches respectively of said bridges in parallel connection with each other relative to said voltage supply means, and a regulator having an output circuit connected across said other pair of bridge points to impress variable regulating voltage thereon and having two cumulative control windings for controlling said regulating voltage, said control windings being connected across said respective armatures for controlling said regulator to maintain the sum of the voltages across said armatures substantially constant.

4. A control system for a rewinder drive, comprising two winder motors each having an armature and a field winding, current supply means, said two armatures being connected in series with each other to said current supply means with such polarities of connection as to produce re-' spective torques in the wind-up sense, constant voltage supply means, said two field windings being connected in parallel to each other to said voltage supply means, a regulating generator having an armature circuit to provide variable regulating voltage and having a pattern field circuit and two mutually cumulative pilot field circuits difierentially related to said pattern field circuit, said motor field windings being connected with said armature circuit in inverse relation so that said regulating voltage strengthens the resultant excitation of one and weakens that of the other motor field winding, and said two pilot field windings being connected across said respective motor armatures for causing said generator to maintain the sum of the voltages across said motor armatures at a substantially constant value determined by the excitation of said pattern field circuit.

5. A control system for a rewinder drive, comprising two winder motors each having an armature and a field winding, current supply means, said two armatures being connected in series with each other to said current supply means with such polarities of connection as to produce respective torques in the wind-up sense, a, bridge circuit having four loop-connected branches and two pairs of diagonal points, voltage supply means of substantially constant voltage connected across one pair of said points, a, regulating generator having an armature circuit connected across said other pair of points to provide regulating voltage for strengthening the excitation of one field winding and weakening the excitation of the other field winding, said regulating generator having a pattern field winding connected to said voltage supply means to receive normally constant excitation and having pilot field means differentially related to said pattern field winding, said pilot field means having two cumulative circuits connected across said respective motor armatures.

6. A control system for a rewinder drive, comprising two winder motors each having an armature and a field winding, current supply means, said two armatures being connected in series with each other to said current supply means with such polarities of connection as to produce respective torques in the wind-up sense, a, bridge circuit having four loop-connected branches and two pairs of diagonal points between said branches, constant voltage supply means connected across one pair of said bridge points, said field windings being disposed in adjacent branches respectively of said bridge in parallel connection with each other relative to said voltage supply means, and a regulating generator having an armature circuit connected across said other pair of points to provide regulating voltage and having a pattern field winding and two pilot field windings for jointly controlling said regulating voltage, reversing switch means connecting said pattern field winding with said voltage supply means, said pilot field windings being both differentially related to said pattern field winding and connected across said respective motor armatures.

7. A control system for a rewinder reel drive, comprising two reel motors each having an armature and a field winding, current supply means, said two armatures being connected to said current supply means, two voltage supply means of which one has substantially constant voltage while the other has an amplifying regulator for l wiiing var-iahlg m u ins o age. said field windings bein conneciie p a lel m at on 1 each other 0;a e at said veltages 31y :31 9, 35 and being -00 meted seri s mlamn 3w otherrwit'h sai 2i1h r voltage-$ 1 9 5 mfi si re uia'fior ing two. nu a' vs-eomml ircuits CGHXIBOtfid across aid respectivg mots *buras.

- 8. A 'contro'l system far a e ind r xe l fix-Ne. @om risMg tw r lmamrsseachhav n ma.- ture and a field w nd n nu nt s pply means. said =two armatures being connected to said pm. rent asupzzzls' meansw vo age su ply mew- 411; w c n has s anti l cqnstam wl a fi mle m w ha an ampfii in QQfiI-Q m n airmaww a rwi f9? 1?; .yi iin friable mgulating a a, ai fie d ind n s Min $011: nested. iri parallgl r el-atiarg to I 'l'jlpthi' one of said voltage supply megngl v H ngste series mlation'tp 'lgam 'Qtllr it} said apmahune circuit, sa ggrgergtbyhavihg' fieljd 266m 0 cgmpu n two v glmul midfie 1.0 mote armahur fi 

